WO2009113416A1 - Communication system, transmission device, and reception device - Google Patents

Communication system, transmission device, and reception device Download PDF

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Publication number
WO2009113416A1
WO2009113416A1 PCT/JP2009/053809 JP2009053809W WO2009113416A1 WO 2009113416 A1 WO2009113416 A1 WO 2009113416A1 JP 2009053809 W JP2009053809 W JP 2009053809W WO 2009113416 A1 WO2009113416 A1 WO 2009113416A1
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WO
WIPO (PCT)
Prior art keywords
image
display
synchronization signal
frame
unit
Prior art date
Application number
PCT/JP2009/053809
Other languages
French (fr)
Japanese (ja)
Inventor
藤男 奥村
修 石橋
雅雄 今井
Original Assignee
日本電気株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 日本電気株式会社 filed Critical 日本電気株式会社
Priority to JP2010502769A priority Critical patent/JP5541153B2/en
Priority to US12/920,392 priority patent/US8587680B2/en
Publication of WO2009113416A1 publication Critical patent/WO2009113416A1/en

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N7/00—Television systems
    • H04N7/08—Systems for the simultaneous or sequential transmission of more than one television signal, e.g. additional information signals, the signals occupying wholly or partially the same frequency band, e.g. by time division
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T1/00—General purpose image data processing
    • G06T1/0021—Image watermarking
    • G06T1/0085—Time domain based watermarking, e.g. watermarks spread over several images
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G5/00—Control arrangements or circuits for visual indicators common to cathode-ray tube indicators and other visual indicators
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
    • H04N21/40—Client devices specifically adapted for the reception of or interaction with content, e.g. set-top-box [STB]; Operations thereof
    • H04N21/41—Structure of client; Structure of client peripherals
    • H04N21/414—Specialised client platforms, e.g. receiver in car or embedded in a mobile appliance
    • H04N21/41415—Specialised client platforms, e.g. receiver in car or embedded in a mobile appliance involving a public display, viewable by several users in a public space outside their home, e.g. movie theatre, information kiosk
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N7/00—Television systems
    • H04N7/025—Systems for the transmission of digital non-picture data, e.g. of text during the active part of a television frame
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
    • G06F3/14—Digital output to display device ; Cooperation and interconnection of the display device with other functional units
    • G06F3/147—Digital output to display device ; Cooperation and interconnection of the display device with other functional units using display panels
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T2201/00—General purpose image data processing
    • G06T2201/005—Image watermarking
    • G06T2201/0051—Embedding of the watermark in the spatial domain
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2358/00—Arrangements for display data security
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2380/00—Specific applications
    • G09G2380/06—Remotely controlled electronic signs other than labels
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G5/00—Control arrangements or circuits for visual indicators common to cathode-ray tube indicators and other visual indicators
    • G09G5/12—Synchronisation between the display unit and other units, e.g. other display units, video-disc players

Definitions

  • the present invention relates to a communication system for transmitting information by an image or a moving image displayed on a display or the like, and a transmission device and a reception device used in the communication system.
  • a visible light communication technique for transmitting information by an image or a moving image displayed on a display or the like
  • a specific two-dimensional code (QR code) or the like is displayed on a part of the display image, and the two-dimensional image is displayed by a camera such as a mobile phone.
  • QR code specific two-dimensional code
  • Systems are known in which a code is imaged and information is received.
  • failure diagnosis data including an abnormality signal indicating the abnormality is generated, and the failure diagnosis data is represented by a symbol code (barcode or two-dimensional).
  • a symbol code barcode or two-dimensional
  • Japanese Laid-Open Patent Publication No. 2006-020204 discloses a server device specified by information of a read two-dimensional code, which reads a two-dimensional code printed on a display medium with a terminal device and provides contents such as an image and sound. A configuration is described in which various contents are acquired by accessing the.
  • an object of the present invention is to provide a communication system capable of visible light communication by simple means without impairing the beauty of public images, and a transmission device and a reception device used in the communication system.
  • the communication system of the present invention outputs an image signal for displaying a first image, a second image, and an inverted image of the second image in a time-sharing manner, and the second image.
  • the transmission device of the present invention includes a display unit that displays a first image, a second image, and an inverted image of the second image; A control unit for displaying the first image, the second image, and the inverted image on the display unit in a time-sharing manner; A synchronization signal generator for transmitting a second image synchronization signal synchronized with the display of the second image;
  • the receiving device of the present invention receives a second image synchronization signal that is transmitted from the transmission device and is synchronized with the display of the second image, and based on the received second image synchronization signal, A synchronization signal processing unit for instructing the shooting timing of the second image; An imaging unit that captures the second image according to an instruction from the synchronization signal processing unit; A display unit for displaying the second image photographed by the photographing unit; Have
  • FIG. 1A is a schematic diagram illustrating a configuration example of a communication system according to the first embodiment.
  • 1B is a schematic diagram illustrating a configuration example of a network system using the communication system illustrated in FIG. 1A.
  • FIG. 2 is a block diagram illustrating a configuration example of the display device and the transmission device illustrated in FIG. 1A.
  • FIG. 3 is a block diagram illustrating a configuration example of the receiving apparatus illustrated in FIG. 1A.
  • FIG. 4 is a schematic diagram illustrating an operation example of the transmission apparatus according to the first embodiment.
  • FIG. 5 is a schematic diagram illustrating an operation example of a transmission device and an optical shutter used in the secure display technology.
  • FIG. 6 is a schematic diagram illustrating an operation example of the transmission apparatus according to the second embodiment.
  • FIG. 1A is a schematic diagram illustrating a configuration example of a communication system according to the first embodiment.
  • 1B is a schematic diagram illustrating a configuration example of a network system using the communication system illustrated in FIG. 1A
  • FIG. 7 is a schematic diagram illustrating another operation example of the transmission apparatus according to the second embodiment.
  • FIG. 8 is a schematic diagram illustrating an operation example of the transmission apparatus according to the third embodiment.
  • FIG. 9 is a diagram illustrating another operation example of the transmission apparatus according to the third embodiment.
  • FIG. 9A illustrates an operation example in which flicker is easily perceived
  • FIG. 9B illustrates an operation in which flicker is difficult to perceive. It is a schematic diagram which shows an example.
  • FIG. 10 is a schematic diagram illustrating an operation example of the receiving apparatus according to the fourth embodiment.
  • a display device that displays a public image and an image (secret image) provided only to a specific user in a time-sharing manner, and a light that is synchronized with the display timing of the secret image.
  • secure display technology in combination with an optical shutter that transmits light.
  • a public image provided to an unspecified person by a display device, a secret image provided only to a specific user, and an inverted image of the secret image are displayed in a time-sharing manner within one frame, and the user
  • the optical shutter existing in front of is switched to the transmission state in synchronization with the display timing of the secret image.
  • the secret image is visually recognized by the user who uses the optical shutter, and the secret image is superimposed on the inverted image to a non-specific person (public) who does not use the optical shutter to create a halftone (gray) image. Therefore, only the public image is visually recognized.
  • the “first image” recited in the claims corresponds to the public image
  • the “second image” corresponds to the secret image.
  • an optical shutter is required to visually recognize the secret image, so that users who provide the secret image are limited.
  • a URL Uniform Resource Locator
  • a server device that displays detailed information about a product displayed as a public image by a public image and provides a detailed image of the product displayed as a secret image with a two-dimensional code, etc. If the two-dimensional code can be acquired without using it, it is preferable for the convenience of the user to improve.
  • FIG. 1A is a schematic diagram illustrating a configuration example of a communication system according to the first embodiment
  • FIG. 1B is a schematic diagram illustrating a configuration example of a network system using the communication system illustrated in FIG. 1A.
  • the communication system includes a display device 1 that displays a public image, a secret image, and a reverse image thereof in a time-sharing manner, and an image for causing the display device 1 to display each image.
  • Transmitting device 3 that outputs a signal
  • receiving device 2 owned by a user that acquires a public image or a secret image from an image displayed on display device 1, and various types of receiving device 2 via known communication means
  • the configuration includes a data server 4 installed in the vicinity of the display device 1 or the transmission device 3 for transmitting content data.
  • a user who uses the communication system of the present embodiment points a camera (not shown) included in the receiving device 2 toward the display image of the display device 1 and is displayed on the display unit of the receiving device 2.
  • the public image is photographed while visually recognizing the public image.
  • the image captured at this time may be the entire public image or a part of the public image.
  • the user can display the public image or a part of the image (for example, a product displayed as an advertisement) on the receiving device 2 and receive the secret image corresponding to the shooting position of the public image. It can be displayed on the device 2. Further, the user can acquire various contents provided by using the secret image by the receiving device 2.
  • the secret image acquired by the receiving device 2 is access data to the data server 4 using a two-dimensional code or the like
  • the data server 4 Data of various contents can be acquired.
  • the data server 4 is not necessarily required, and may not be provided when only the secret image is provided.
  • the communication system shown in FIG. 1A can realize a network system that provides users with various contents and information services by connecting to a network such as the Internet.
  • the secret image is URL data using, for example, a two-dimensional code
  • the user decodes the two-dimensional code by the receiving device 2 to acquire the URL
  • a network such as the Internet
  • the data of various contents can be acquired from the server device (Web site) designated by the URL via the URL.
  • the secret image is, for example, a moving image
  • the user can acquire video information such as a video clip using the receiving device 2, and audio information (two-dimensional code or the like displayed) (Including music etc.).
  • FIG. 2 is a block diagram showing a configuration example of the display device and the transmission device shown in FIG. 1A
  • FIG. 3 is a block diagram showing a configuration example of the reception device shown in FIG. 1A.
  • the transmission apparatus 3 includes a level detection unit 11, a first luminance modulation unit 12, a second luminance modulation unit 13, an inverted image generation unit 14, a selector 15, a synchronization signal generation unit 16, and a control unit.
  • the display device 1 includes a video memory 17 and a display unit 19.
  • the level detection unit 11 detects the luminance (image signal level) of the public image and notifies the first luminance modulation unit 12 and the second luminance modulation unit 13 of the detection result.
  • the first luminance modulation unit 12 changes the luminance (image signal level) of the public image as necessary based on the detection result of the level detection unit 11.
  • the second luminance modulation unit 13 changes the luminance (image signal level) of the secret image as necessary based on the detection result of the level detection unit 11.
  • the inverted image generation unit 14 generates an image signal corresponding to the inverted image using the image signal of the secret image after the level change by the second luminance modulation unit 13.
  • an image signal of the inverted image for example, when the image signal level of the secret image is set to the positive direction, an image signal having the same absolute value as that of the secret image and the image signal level of the negative direction is generated. do it.
  • the selector 15 selects the image signal of the public image output from the first luminance modulation unit 12, the image signal of the secret image output from the second luminance modulation unit 13, or the reverse image generated by the reverse image generation unit 14.
  • the image signals are switched in accordance with instructions from the control unit 18 and are sequentially output to the video memory 17.
  • the synchronization signal generator 16 generates and transmits a public image synchronization signal synchronized with the display start and display end of the public image and a secret image synchronization signal synchronized with the display start and display end of the secret image.
  • the control unit 18 controls the operations of the selector 15 and the synchronization signal generating unit 16 in accordance with the frame configuration of the image displayed on the display unit 19.
  • the video memory 17 sequentially holds the image signal of the public image, the secret image or the reverse image selected by the selector 15 as image data. Note that the video memory 17 may be provided not in the display device 1 but in the transmission device 3.
  • the display unit 19 sequentially displays a public image, a secret image, or a reverse image according to the image data stored in the video memory 17.
  • the transmission device 3 shown in FIG. 2 can be realized by an A / D converter for processing an image signal, a CPU, a DSP, a logical operation circuit, or the like that executes processing according to a program.
  • the display device 1 may be a liquid crystal display, an LED display, a DLP type projector device, an organic EL display, a PDP, or the like.
  • the reception device 2 includes an imaging unit 21, a synchronization signal processing unit 22, a multiplier distributor 23, an embedded signal processing unit 24, a video memory 25, a display unit 26, a transmission / reception unit 27, and a control unit 28.
  • the sound signal processing unit 29 and the communication unit 30 are provided.
  • the photographing unit 21 includes a camera, photographs an image displayed on the display unit 19 of the display device 1 in accordance with an instruction from the synchronization signal processing unit 22, and outputs the image to the multiplier / distributor 23.
  • the synchronization signal processing unit 22 includes a receiving unit that receives the public image synchronization signal and the secret image synchronization signal transmitted from the transmission device 3, and captures images based on the received public image synchronization signal and secret image synchronization signal.
  • the unit 21 is instructed to shoot the public image or the secret image, and outputs the public image synchronization signal or the secret image synchronization signal to the multiplier distributor 23.
  • the public image synchronization signal and the secret image synchronization signal are obtained by using an optical communication means using infrared rays or a known short-range wireless communication means such as Bluetooth, UWB, ZigBee, etc. 16 to the synchronization signal processing unit 22 included in the receiving device 2.
  • the multiplier distributor 23 changes the luminance (image signal level) of the image signal of the public image or secret image output from the photographing unit 21 and distributes it to the video memory 25 and the embedded signal processing unit 24.
  • the video memory 25 stores the image signal output from the multiplier distributor 23 or the control unit 28 as image data.
  • the display unit 26 displays a public image or a secret image according to the image data stored in the video memory 25.
  • the embedded signal processing unit 24 performs necessary signal processing on the image signal of the secret image acquired by the imaging unit 21. For example, when the secret image photographed by the photographing unit 21 is a two-dimensional code, the embedded signal processing unit 24 decodes the two-dimensional code. The signal processing result of the embedded signal processing unit 24 is output to the control unit 28.
  • the control unit 28 uses the transmission / reception unit 27 and the communication unit 30 to transmit voice (including music) data, character data, image data, Various content data such as moving image data is acquired.
  • voice including music
  • character data character data
  • image data image data
  • Various content data such as moving image data is acquired.
  • the control unit 28 acquires various content data from a server device or the like in the network specified by the URL using the communication unit 30.
  • various content data are acquired from the data server 4 using the transmission / reception unit 27.
  • the acquired sound data is output to the sound signal processing unit 29, and character data, image data, moving image data, and the like are stored in the video memory 25 as image data.
  • the sound signal processing unit 29 includes an amplifier that amplifies an audio signal, a speaker that outputs audio, and the like, converts audio data supplied from the control unit 28 into an audio signal, and outputs audio through the speaker.
  • the transmitting / receiving unit 27 is communicably connected to the data server 4 and receives various content data from the data server 4 in accordance with instructions from the control unit 28.
  • the transmission / reception unit 27 and the data server 4 may transmit and receive various types of content data using optical communication means using infrared rays or the like, or well-known short-range wireless communication means such as Bluetooth, UWB, ZigBee.
  • the communication unit 30 is communicably connected to a network such as the Internet by a known wireless communication unit, and receives various content data from a server device or the like specified by a URL in the network according to an instruction from the control unit 28.
  • the receiving device 2 includes a mobile phone and a PDA (Personal Digital Assistant) equipped with a camera for taking an image and a receiving device for receiving the public image synchronization signal and the secret image synchronization signal transmitted from the transmission device 3.
  • a portable terminal device such as a notebook personal computer is used.
  • FIG. 4 is a schematic diagram illustrating an operation example of the transmission apparatus according to the first embodiment.
  • the transmission apparatus 3 displays a public image, a secret image, and an inverted image in a time-division manner within one frame, as in the above-described secure display technology.
  • the display order of public images, secret images, and reverse images within one frame is arbitrary.
  • the synchronization signal generator 16 transmits a public image synchronization signal synchronized with the display start and display end of the public image, and a secret image synchronization signal synchronized with the display start and display end of the secret image.
  • the receiving device 2 receives the public image synchronization signal and the secret image synchronization signal by the synchronization signal processing unit 22, respectively, and captures and displays the public image or the secret image at the position specified by the user's operation by the imaging unit 21. Displayed on the unit 26.
  • the secret image does not necessarily have to be displayed on the display unit 26. Instead of the secret image, the secret image is acquired from the network or the data server 4 based on the signal processing result of the embedded signal processing unit 24 or the signal processing result.
  • Various kinds of content data may be displayed.
  • the receiving device 2 displays the secret image on the display unit 26 for a time that allows the user to confirm the secret image, and then obtains the result of signal processing of the embedded signal processing unit 24 or the network or the data server 4.
  • Various content data may be displayed.
  • an image sensor such as a CCD (Charge Coupled Devices) or a CMOS is used for a camera included in a mobile terminal device used as the receiving device 2.
  • a CCD Charge Coupled Devices
  • CMOS complementary metal-oxide-semiconductor
  • the photographing unit 21 uses these image pickup elements, in general, in order to reduce noise and improve light reception sensitivity, charges generated in the CCD and CMOS according to the amount of received light are integrated for a certain period (for example, one frame period). Operate in accumulation mode. Therefore, if the display period of the public image or the secret image is not detected by any means, the photographing unit 21 outputs a composite image of the public image and the secret image.
  • the receiving device 2 of the present embodiment uses the public image synchronization signal and the secret image synchronization signal transmitted from the transmission device 3 to detect the start and end of the integration period when the required public image or secret image is captured. To do. Therefore, the receiving device 2 can shoot the public image and the secret image at the position designated by the user operation without being combined by the shooting unit 21. Further, in the receiving apparatus 2 of the present embodiment, since the secret image is captured using the secret image synchronization signal, the image quality of the secret image is deteriorated by combining the secret image and the inverted image, that is, for visible light communication. Deterioration of the signal level used is prevented.
  • visible light communication can be performed by simple means without impairing the beauty of public images.
  • FIG. 6 is a schematic diagram illustrating an operation example of the transmission apparatus according to the second embodiment.
  • the transmission device 3 sets the display period of the public image longer than the display period of the secret image and the reverse image.
  • a frame for displaying only a public image hereinafter referred to as a public image frame
  • the public image, the secret image, and the reverse image shown in the first embodiment are time-divisionally divided.
  • a frame to be displayed (hereinafter referred to as a secure frame) is periodically inserted between a plurality of consecutive public image frames. If the display period of the public image is set longer than the display period of the secret image or the reverse image in this way, the brightness of the public image displayed on the display device 1 is improved and the contrast is increased. Therefore, the image quality of the displayed public image is increased. Will improve.
  • the control unit 18 of the transmission device 3 may cause the selector 15 to select an optimal image signal in accordance with the frame configuration.
  • the synchronization signal generator 16 of the transmission device 3 starts the display of the public image according to the frame configuration of the image displayed on the display device 1, and starts the display and display of the public image synchronization signal and the secret image synchronized with the display end.
  • a secret image synchronization signal synchronized with the end may be transmitted. Since the configurations of the display device 1, the transmission device 3, and the reception device 2 and other operations are the same as those in the first embodiment, description thereof is omitted.
  • the secret image is directly photographed by the photographing unit 21 of the receiving device 2 without passing through the optical shutter, stored in the video memory 25 and displayed. Therefore, it is not necessary to consider a decrease in the brightness of the secret image unlike the secure display technology.
  • the secure frame may be provided every three frames as shown in FIG. 7 (a), or may be provided every four frames as shown in FIG. 7 (b).
  • the configuration may be such that a secure frame is provided for each.
  • the number of public image frames is increased, the brightness of the public image is improved and the contrast of the public image is increased. However, when the number of public image frames is increased, the chance of acquiring the secret image is reduced. Therefore, if the update frequency of secret images is high (video display etc.) or if it is desired to reduce the time required to display the secret image on the receiving device 2, an upper limit is set for the number of increase of public image frames as necessary. It is preferable to do.
  • FIG. 8 is a schematic diagram illustrating an operation example of the transmission apparatus according to the third embodiment.
  • FIG. 9 is a diagram showing another operation example of the transmission apparatus according to the third embodiment.
  • FIG. 9A shows an operation example in which flicker is easily perceived
  • FIG. 9B shows that it is difficult to perceive flicker.
  • It is a schematic diagram which shows an operation example. Since the configurations of the display device 1, the transmission device 3, and the reception device 2 and other operations are the same as those in the first embodiment and the second embodiment, description thereof is omitted.
  • secure frames are randomly inserted into a plurality of consecutive public image frames (see FIG. 8). By doing in this way, the flicker of the public image displayed on the display apparatus 1 is suppressed.
  • the public image frame and the secure frame may be switched by causing the control unit 18 of the transmission device 3 to select the optimum image signal in accordance with the frame configuration.
  • the synchronization signal generation unit 16 of the transmission device 3 includes a public image synchronization signal synchronized with the display start and display end of the public image and a secret image synchronized with the display start and display end according to the frame configuration to be displayed.
  • a synchronization signal may be transmitted. Since the configurations of the display device 1, the transmission device 3, and the reception device 2 and other operations are the same as those in the first embodiment, description thereof is omitted.
  • the following method is also effective as a method of suppressing the flicker of public images displayed on the display device 1.
  • the luminance of the public image for each frame is made the same by changing the image signal level of the public image of the public image frame and that of the secure frame.
  • the first luminance modulation unit 12 reduces the image signal level of the public image in the public image frame according to the ratio of the public image display period of the public image frame and the secure frame.
  • the second luminance modulation unit 13 increases the image signal level of the public image in the secure frame according to the ratio of the display period of the public image frame and the public image of the secure frame.
  • the first luminance modulation unit 12 sets the image signal level of the public image frame to 1/3.
  • the second luminance modulation unit 13 triples the image signal level of the secret image frame. Also in these methods, flickering of public images displayed on the display device 1 is suppressed.
  • making the brightness of the public image of the public image frame and the secure frame the same means that the peak value of the image signal level of the public image for each frame is the same, and the average value of the image signal level of the public image for each frame Are the same or a combination of these processes.
  • FIG. 10 is a schematic diagram illustrating an operation example of the receiving apparatus according to the fourth embodiment.
  • the display device 1 displays a mixture of public image frames and secure frames
  • the display of the public image is started and the display end of the public image from the synchronization signal generator 16 of the transmission device 3.
  • the reception apparatus 2 obtains a public image and a secret image that have different brightness (luminance) because the integration period is different. Therefore, when the public image displayed on the display unit 26 of the receiving device 2 is switched to the secret image, the screen of the secret image is perceived as an image with a dark contrast and a low contrast.
  • the multiplier / distributor 23 causes the luminance of the public image and the secret image displayed on the display unit 26 of the receiving device 2 according to the ratio of the display period of the public image and the secret image.
  • the image signal level of the secret image acquired by the photographing unit 21 is increased so as to be the same.
  • the image signal level of the public image acquired by the photographing unit 21 is lowered so that the brightness of the public image and the secret image displayed on the display unit 26 of the receiving device 2 are the same.
  • the multiplier distributor 23 sets the image signal level of the secret image. Triple.
  • the multiplier distributor 23 sets the image signal level of the public image to 1/3. In this way, since the brightness of the public image and the secret image becomes the same, the public image and the secret image are displayed on the display unit 26 of the receiving device 2 with the same brightness.
  • the period from the display start of the public image synchronization signal generated by the synchronization signal generation unit 16 of the transmission device 3 to the display end is set. What is necessary is just to make it correspond to the display period (refer to 10 (c)) of a secret image.
  • the display period of the public image by the display device 1 is three times the display period of the secret image
  • the period from the display start to the display end of the public image synchronization signal generated by the synchronization signal generator 16 is actually displayed. Set to 1/3 of the period.
  • the public image and the secret image displayed on the display unit 26 of the receiving device 2 are displayed with the same brightness. Is done.
  • the public image and the secret image are displayed on the display unit 26 of the receiving device 2 with the same brightness.
  • the same brightness of the public image and the secret image means that the peak value of the image signal level of the public image and the secret image is the same, and the average value of the image signal level of the public image and the secret image is the same. Or a combination of these processes.
  • the display device 1 displays a public image and a halftone (gray) image in which the secret image and its inverted image are superimposed. For this reason, when a dark (black) image is included in the public image, a so-called black float occurs in which the part feels brighter than the actual image. That is, the contrast of the public image displayed on the display device 1 is lowered.
  • the transmission device 3 determines the main color and displays the corresponding blue or red secret image.
  • the device 1 is displayed in a secure frame. For example, when the dark part in the public image is a strong blue image, the display device 1 displays the blue secret image and its reverse image on the corresponding part in the secure frame. In this way, since the halftone in which the secret image and the inverted image are superimposed in the corresponding part is blue, a decrease in contrast of the dark part in the public image is suppressed.
  • the display device 1 displays the red secret image and its inverted image at the corresponding part in the secure frame. In this way, since the halftone in which the secret image and the inverted image are superimposed in the corresponding part is red, the decrease in contrast of the dark part in the public image is suppressed.
  • the display device 1 when there are a plurality of dark parts in the public image, and there are a part where a strong red image is displayed and a part where a strong blue image is displayed, the display device 1 has red or red at each corresponding part in the secure frame. A blue secret image and its reverse image are displayed. In this way, since the halftone in which the secret image and the reverse image are superimposed in the corresponding part is red or blue, a decrease in contrast of the dark part in the public image is suppressed.
  • the secret image displayed in the present embodiment is preferably a coded image such as a two-dimensional code or a one-dimensional code.
  • the secret image displayed in the present embodiment is not limited to the coded image, and any image can be used as long as it does not feel strange even if it includes a red or blue portion by the above processing. Such an image may be used.
  • a secret image made up of a normal color image and its inverted image may be displayed in a secure frame at a bright part in a public image.
  • the secret image and the reverse image are displayed in blue or red
  • blue or red is displayed stronger in the public image. Therefore, if the blue or red image signal level of the public image is lowered according to the halftone image signal level in which the secret image and the inverted image are superimposed, the secret image and the entire inverted image are displayed as a blue or red image. It is also possible to do.
  • the level detection unit 11 shown in FIG. 2 detects the image signal level and color of a public image for each area of a predetermined size, and the detection result is obtained.
  • the first luminance modulation unit 12 and the second luminance modulation unit 13 are notified. Based on the detection result of the level detection unit 11, the first luminance modulation unit 12 reduces and outputs the blue or red image signal level of the public image as necessary.
  • the second luminance modulation unit 13 Based on the detection result of the level detection unit 11, the second luminance modulation unit 13 outputs an area of a predetermined size set in advance or converts the entire secret image into a blue or red image. Since the other configurations of the transmission device 3 and the configurations of the display device 1 and the reception device 2 are the same as those in the first embodiment, description thereof is omitted.

Abstract

A transmission device displays a public image (a first image) provided to unspecified users, a secret image (a second image) provided to particular users, and a reversed image of the secret image by time division; and transmits a secret image synchronization signal synchronized with display of the secret image. A reception device receives the secret image synchronization signal transmitted from the transmission device and causes an imaging unit to capture the secret image displayed on the transmission device by using the secret image synchronization signal, for display on a display unit.

Description

通信システム、送信装置及び受信装置COMMUNICATION SYSTEM, TRANSMISSION DEVICE, AND RECEPTION DEVICE
　本発明はディスプレイ等に表示する画像や動画像によって情報を伝達する通信システム、並びに該通信システムで用いる送信装置及び受信装置に関する。 The present invention relates to a communication system for transmitting information by an image or a moving image displayed on a display or the like, and a transmission device and a reception device used in the communication system.
　ディスプレイ等に表示する画像や動画像により情報を伝達する可視光通信技術としては、表示画像の一部に特定の二次元コード（ＱＲコード）等を表示し、携帯電話機等のカメラにより該二次元コードを撮像して情報を受信するシステムが知られている。 As a visible light communication technique for transmitting information by an image or a moving image displayed on a display or the like, a specific two-dimensional code (QR code) or the like is displayed on a part of the display image, and the two-dimensional image is displayed by a camera such as a mobile phone. Systems are known in which a code is imaged and information is received.
　例えば特開２００７－１６３２３３号公報には、車両用ナビゲーションシステムで異常を検出した場合に、該異常を示す異常信号を含む故障診断データを生成し、故障診断データをシンボルコード（バーコードや二次元コード）に変換して表示装置に表示し、表示されたシンボルコードをユーザが携帯端末装置で読み取ることで故障診断データを視認できるようにした構成が記載されている。 For example, in Japanese Patent Application Laid-Open No. 2007-163233, when an abnormality is detected in a vehicle navigation system, failure diagnosis data including an abnormality signal indicating the abnormality is generated, and the failure diagnosis data is represented by a symbol code (barcode or two-dimensional). A configuration is described in which failure diagnosis data can be visually recognized by a user reading the displayed symbol code with a portable terminal device.
　また、特開２００６－０２０２０４号公報には、表示媒体に印刷された二次元コードを端末装置で読み取り、画像や音声等のコンテンツを提供する、読み取った二次元コードの情報で特定されるサーバ装置にアクセスして各種のコンテンツを取得する構成が記載されている。 Japanese Laid-Open Patent Publication No. 2006-020204 discloses a server device specified by information of a read two-dimensional code, which reads a two-dimensional code printed on a display medium with a terminal device and provides contents such as an image and sound. A configuration is described in which various contents are acquired by accessing the.
　しかしながら上記したような背景技術の可視光通信技術では、例えば街頭で用いられる大型の表示ディスプレイ等で二次元コードを表示すると、二次元コードが公衆に向けて表示された広告等の画像（公衆画像）の一部を占有するために美観を損なうという問題がある。 However, in the visible light communication technology of the background art as described above, when a two-dimensional code is displayed on, for example, a large display used on a street, an image such as an advertisement (public image) in which the two-dimensional code is displayed to the public. ) To occupy a part of the aesthetics.
　そこで、本発明は、公衆画像の美観を損なうことなく、簡易な手段により可視光通信が可能な通信システム、並びに該通信システムで用いる送信装置及び受信装置を提供することを目的とする。 Therefore, an object of the present invention is to provide a communication system capable of visible light communication by simple means without impairing the beauty of public images, and a transmission device and a reception device used in the communication system.
　上記目的を達成するため本発明の通信システムは、第１の画像と第２の画像と該第２の画像の反転画像とを時分割で表示するための画像信号を出力すると共に、前記第２の画像の表示と同期する第２の画像用同期信号を送信する送信装置と、
　前記送信装置より出力された画像信号に基づく画像を表示する表示装置と、
　前記第２の画像用同期信号を受信し、前記第２の画像用同期信号を用いて前記送信装置に表示された前記第２の画像を前記撮影部により撮影する受信装置と、
を有する。 In order to achieve the above object, the communication system of the present invention outputs an image signal for displaying a first image, a second image, and an inverted image of the second image in a time-sharing manner, and the second image. A transmission device for transmitting a second image synchronization signal synchronized with the display of the image of
A display device for displaying an image based on the image signal output from the transmission device;
A receiver that receives the second image synchronization signal, and that captures the second image displayed on the transmitter using the second image synchronization signal, by the imaging unit;
Have
　一方、本発明の送信装置は、第１の画像、第２の画像及び該第２の画像の反転画像を表示する表示部と、
　前記第１の画像、前記第２の画像及び前記反転画像を前記表示部に時分割で表示させるための制御部と、
　前記第２の画像の表示と同期する第２の画像用同期信号を送信する同期信号発生部と、
を有する。 On the other hand, the transmission device of the present invention includes a display unit that displays a first image, a second image, and an inverted image of the second image;
A control unit for displaying the first image, the second image, and the inverted image on the display unit in a time-sharing manner;
A synchronization signal generator for transmitting a second image synchronization signal synchronized with the display of the second image;
Have
　また、本発明の受信装置は、送信装置から送信される、第２の画像の表示と同期する第２の画像用同期信号を受信し、受信した前記第２の画像用同期信号に基づいて、前記第２の画像の撮影タイミングを指示する同期信号処理部と、
　前記同期信号処理部からの指示にしたがって前記第２の画像を撮影する撮影部と、
　前記撮影部で撮影された前記第２の画像を表示する表示部と、
を有する。 Further, the receiving device of the present invention receives a second image synchronization signal that is transmitted from the transmission device and is synchronized with the display of the second image, and based on the received second image synchronization signal, A synchronization signal processing unit for instructing the shooting timing of the second image;
An imaging unit that captures the second image according to an instruction from the synchronization signal processing unit;
A display unit for displaying the second image photographed by the photographing unit;
Have
図１Ａは、第１の実施の形態の通信システムの一構成例を示す模式図である。FIG. 1A is a schematic diagram illustrating a configuration example of a communication system according to the first embodiment. 図１Ｂは、図１Ａに示した通信システムを利用したネットワークシステムの一構成例を示す模式図である。1B is a schematic diagram illustrating a configuration example of a network system using the communication system illustrated in FIG. 1A. 図２は、図１Ａに示した表示装置及び送信装置の一構成例を示すブロック図である。FIG. 2 is a block diagram illustrating a configuration example of the display device and the transmission device illustrated in FIG. 1A. 図３は、図１Ａに示した受信装置の一構成例を示すブロック図である。FIG. 3 is a block diagram illustrating a configuration example of the receiving apparatus illustrated in FIG. 1A. 図４は、第１の実施の形態の送信装置の動作例を示す模式図である。FIG. 4 is a schematic diagram illustrating an operation example of the transmission apparatus according to the first embodiment. 図５は、セキュアディスプレイ技術で利用する送信装置及び光シャッターの動作例を示す模式図である。FIG. 5 is a schematic diagram illustrating an operation example of a transmission device and an optical shutter used in the secure display technology. 図６は、第２の実施の形態の送信装置の動作例を示す模式図である。FIG. 6 is a schematic diagram illustrating an operation example of the transmission apparatus according to the second embodiment. 図７は、第２の実施の形態の送信装置の他の動作例を示す模式図である。FIG. 7 is a schematic diagram illustrating another operation example of the transmission apparatus according to the second embodiment. 図８は、第３の実施の形態の送信装置の動作例を示す模式図である。FIG. 8 is a schematic diagram illustrating an operation example of the transmission apparatus according to the third embodiment. 図９は、第３の実施の形態の送信装置の他の動作例を示す図であり、同図（ａ）はフリッカを知覚し易い動作例、同図（ｂ）はフリッカを知覚し難い動作例を示す模式図である。FIG. 9 is a diagram illustrating another operation example of the transmission apparatus according to the third embodiment. FIG. 9A illustrates an operation example in which flicker is easily perceived, and FIG. 9B illustrates an operation in which flicker is difficult to perceive. It is a schematic diagram which shows an example. 図１０は、第４の実施の形態の受信装置の動作例を示す模式図である。FIG. 10 is a schematic diagram illustrating an operation example of the receiving apparatus according to the fourth embodiment.
　次に本発明について図面を用いて説明する。 Next, the present invention will be described with reference to the drawings.
　上述した背景技術の問題点に対処する方法として、例えば公衆画像と特定のユーザにのみ提供する画像（秘密画像）とを時分割に表示する表示装置と、秘密画像の表示タイミングに同期して光を透過させる光シャッターとを組み合わせた、いわゆるセキュアディスプレイ技術がある。 As a method for dealing with the problems of the background art described above, for example, a display device that displays a public image and an image (secret image) provided only to a specific user in a time-sharing manner, and a light that is synchronized with the display timing of the secret image. There is so-called secure display technology in combination with an optical shutter that transmits light.
　セキュアディスプレイ技術では、表示装置により不特定者向けに提供する公衆画像と、特定のユーザにのみ提供する秘密画像と、該秘密画像の反転画像とを１フレーム内で時分割に表示すると共に、ユーザの目前に存在する光シャッターを秘密画像の表示タイミングに同期させて透過状態に切り替える。これにより光シャッターを用いるユーザには秘密画像のみが視認され、光シャッターを用いない周囲の不特定者（公衆）には、秘密画像がその反転画像と重畳されて中間調（灰色）の画像になるため、公衆画像のみが視認される。なお、特許請求の範囲に記載した「第１の画像」は上記公衆画像に対応し、「第２の画像」は上記秘密画像に対応している。 In the secure display technology, a public image provided to an unspecified person by a display device, a secret image provided only to a specific user, and an inverted image of the secret image are displayed in a time-sharing manner within one frame, and the user The optical shutter existing in front of is switched to the transmission state in synchronization with the display timing of the secret image. As a result, only the secret image is visually recognized by the user who uses the optical shutter, and the secret image is superimposed on the inverted image to a non-specific person (public) who does not use the optical shutter to create a halftone (gray) image. Therefore, only the public image is visually recognized. The “first image” recited in the claims corresponds to the public image, and the “second image” corresponds to the secret image.
　このセキュアディスプレイ技術を利用すれば、不特定者に向けて公衆画像を提供しつつ、光シャッターを持つユーザに秘密画像を用いて各種の情報を提供できる。そのため、公衆画像の美観を損なうことはない。 By using this secure display technology, it is possible to provide various information using a secret image to a user having an optical shutter while providing a public image to an unspecified person. Therefore, the beauty of public images is not impaired.
　しかしながら、セキュアディスプレイ技術では、上述したように秘密画像を視認するのに光シャッターが必要であるため、秘密画像を提供するユーザが限定されてしまう。一般的な可視光通信では、より簡易に秘密画像で多数のユーザに各種の情報（コンテンツ）を提供できるようにすることが望ましい。 However, in the secure display technology, as described above, an optical shutter is required to visually recognize the secret image, so that users who provide the secret image are limited. In general visible light communication, it is desirable to be able to provide various information (contents) to a large number of users with a secret image more easily.
　例えば、公衆画像により広告等を表示し、秘密画像により該公衆画像で表示された商品の詳細情報を提供するサーバ装置のＵＲＬ（Uniform　Resource　Locator）を二次元コード等で表示する場合、光シャッターを用いることなく該二次元コードを取得できればユーザの利便性が向上するために好ましい。 For example, when displaying a URL (Uniform Resource Locator) of a server device that displays detailed information about a product displayed as a public image by a public image and provides a detailed image of the product displayed as a secret image with a two-dimensional code, etc. If the two-dimensional code can be acquired without using it, it is preferable for the convenience of the user to improve.
　そこで、本発明では、このセキュアディスプレイ技術を利用し、秘密画像により多数のユーザに簡易に各種のコンテンツを提供できる手法を提案する。なお、以下では、セキュアディスプレイ技術と同様に、不特定者に向けて提供する広告等の画像を公衆画像と称し、特定のユーザにのみ提供する画像を秘密画像と称す。
（第１の実施の形態）
　図１Ａは第１の実施の形態の通信システムの一構成例を示す模式図であり、図１Ｂは図１Ａに示した通信システムを利用したネットワークシステムの一構成例を示す模式図である。 Therefore, the present invention proposes a method that can easily provide various contents to a large number of users using a secret image by using this secure display technology. In the following, like the secure display technology, an image such as an advertisement provided to an unspecified person is referred to as a public image, and an image provided only to a specific user is referred to as a secret image.
(First embodiment)
FIG. 1A is a schematic diagram illustrating a configuration example of a communication system according to the first embodiment, and FIG. 1B is a schematic diagram illustrating a configuration example of a network system using the communication system illustrated in FIG. 1A.
　図１Ａに示すように、第１の実施の形態の通信システムは、公衆画像、秘密画像及びその反転画像を時分割で表示する表示装置１と、表示装置１に各画像を表示させるための画像信号を出力する送信装置３と、表示装置１に表示されている画像から公衆画像または秘密画像を取得する、ユーザが所有する受信装置２と、周知の通信手段を介して受信装置２に各種のコンテンツのデータを送信する、表示装置１あるいは送信装置３の近傍に設置されるデータサーバ４とを備えた構成である。 As illustrated in FIG. 1A, the communication system according to the first embodiment includes a display device 1 that displays a public image, a secret image, and a reverse image thereof in a time-sharing manner, and an image for causing the display device 1 to display each image. Transmitting device 3 that outputs a signal, receiving device 2 owned by a user that acquires a public image or a secret image from an image displayed on display device 1, and various types of receiving device 2 via known communication means The configuration includes a data server 4 installed in the vicinity of the display device 1 or the transmission device 3 for transmitting content data.
　図１Ａに示すように、本実施形態の通信システムを利用するユーザは、表示装置１の表示画像に対して受信装置２が備える不図示のカメラを向け、該受信装置２の表示部に表示されている公衆画像を視認しながら該公衆画像を撮影する。このとき撮影する画像は公衆画像全体であってもよく、公衆画像の一部であってもよい。このような操作により、ユーザは公衆画像あるいはその一部の画像（例えば広告表示された商品）を受信装置２に表示させることが可能であり、該公衆画像の撮影位置に対応する秘密画像を受信装置２に表示させることが可能である。また、ユーザは秘密画像を利用して提供される各種のコンテンツを受信装置２により取得できる。例えば、受信装置２で取得した秘密画像が二次元コード等を用いたデータサーバ４へのアクセスデータである場合、該アクセスデータに基づいてデータサーバ４と情報を送受信することで、データサーバ４から各種のコンテンツのデータを取得できる。 As shown in FIG. 1A, a user who uses the communication system of the present embodiment points a camera (not shown) included in the receiving device 2 toward the display image of the display device 1 and is displayed on the display unit of the receiving device 2. The public image is photographed while visually recognizing the public image. The image captured at this time may be the entire public image or a part of the public image. By such an operation, the user can display the public image or a part of the image (for example, a product displayed as an advertisement) on the receiving device 2 and receive the secret image corresponding to the shooting position of the public image. It can be displayed on the device 2. Further, the user can acquire various contents provided by using the secret image by the receiving device 2. For example, when the secret image acquired by the receiving device 2 is access data to the data server 4 using a two-dimensional code or the like, by transmitting / receiving information to / from the data server 4 based on the access data, the data server 4 Data of various contents can be acquired.
　なお、図１Ａに示す通信システムでは、秘密画像を利用してユーザに各種のコンテンツを提供することを想定しているため、該コンテンツのデータを受信装置２に送信するデータサーバ４を備えた構成を示しているが、データサーバ４は、必ずしも必要ではなく、秘密画像のみ提供する場合は無くてもよい。 In the communication system shown in FIG. 1A, since it is assumed that various contents are provided to the user using a secret image, a configuration including a data server 4 that transmits data of the contents to the receiving device 2 However, the data server 4 is not necessarily required, and may not be provided when only the secret image is provided.
　図１Ｂに示すように、図１Ａに示した通信システムは、インターネット等のネットワークと接続することで、ユーザに各種のコンテンツや情報サービスを提供するネットワークシステムを実現できる。 As shown in FIG. 1B, the communication system shown in FIG. 1A can realize a network system that provides users with various contents and information services by connecting to a network such as the Internet.
　このようなネットワークシステムでは、秘密画像が、例えば二次元コード等を用いたＵＲＬのデータである場合、ユーザは、受信装置２により該二次元コードをデコードしてＵＲＬを取得し、インターネット等のネットワークを介して該ＵＲＬで指定されたサーバ装置（Ｗｅｂサイト）から各種のコンテンツのデータを取得できる。 In such a network system, when the secret image is URL data using, for example, a two-dimensional code, the user decodes the two-dimensional code by the receiving device 2 to acquire the URL, and a network such as the Internet The data of various contents can be acquired from the server device (Web site) designated by the URL via the URL.
　また、秘密画像が、例えば動画像である場合、ユーザは、受信装置２を用いてビデオクリップ等の映像情報を取得することが可能であり、二次元コード等を用いて表示された音声情報（音楽等を含む）を取得することも可能である。 In addition, when the secret image is, for example, a moving image, the user can acquire video information such as a video clip using the receiving device 2, and audio information (two-dimensional code or the like displayed) (Including music etc.).
　さらに、秘密画像の秘匿性を利用すれば、オンラインによる物品の購入や決済処理、あるいは株式の取引等、各種の情報サービスをユーザに提供できる。 Furthermore, if the confidentiality of the secret image is used, various information services such as online purchase of goods, settlement processing, and stock transactions can be provided to the user.
　以下、図１Ａに示した通信システム及び図１Ｂに示したネットワークシステムを構成する、表示装置１、送信装置３及び受信装置２の具体例について図面を用いて説明する。 Hereinafter, specific examples of the display device 1, the transmission device 3, and the reception device 2 constituting the communication system illustrated in FIG. 1A and the network system illustrated in FIG. 1B will be described with reference to the drawings.
　図２は図１Ａに示した表示装置及び送信装置の一構成例を示すブロック図であり、図３は図１Ａに示した受信装置の一構成例を示すブロック図である。 FIG. 2 is a block diagram showing a configuration example of the display device and the transmission device shown in FIG. 1A, and FIG. 3 is a block diagram showing a configuration example of the reception device shown in FIG. 1A.
　図２に示すように、送信装置３は、レベル検出部１１、第１の輝度変調部１２、第２の輝度変調部１３、反転画像生成部１４、セレクタ１５、同期信号発生部１６及び制御部１８を備え、表示装置１はビデオメモリ１７及び表示部１９を備えている。 As shown in FIG. 2, the transmission apparatus 3 includes a level detection unit 11, a first luminance modulation unit 12, a second luminance modulation unit 13, an inverted image generation unit 14, a selector 15, a synchronization signal generation unit 16, and a control unit. The display device 1 includes a video memory 17 and a display unit 19.
　レベル検出部１１は、公衆画像の輝度（画像信号レベル）を検出し、その検出結果を第１の輝度変調部１２及び第２の輝度変調部１３に通知する。 The level detection unit 11 detects the luminance (image signal level) of the public image and notifies the first luminance modulation unit 12 and the second luminance modulation unit 13 of the detection result.
　第１の輝度変調部１２は、レベル検出部１１の検出結果を基に必要に応じて公衆画像の輝度（画像信号レベル）を変更する。 The first luminance modulation unit 12 changes the luminance (image signal level) of the public image as necessary based on the detection result of the level detection unit 11.
　第２の輝度変調部１３は、レベル検出部１１の検出結果を基に必要に応じて秘密画像の輝度（画像信号レベル）を変更する。 The second luminance modulation unit 13 changes the luminance (image signal level) of the secret image as necessary based on the detection result of the level detection unit 11.
　反転画像生成部１４は、第２の輝度変調部１３によるレベル変更後の秘密画像の画像信号を用いてその反転画像に対応する画像信号を生成する。反転画像の画像信号としては、例えば秘密画像の画像信号レベルを正方向とした場合、該秘密画像と画像信号レベルの絶対値が同一であり、かつ負方向の画像信号レベルを持つ画像信号を生成すればよい。 The inverted image generation unit 14 generates an image signal corresponding to the inverted image using the image signal of the secret image after the level change by the second luminance modulation unit 13. As an image signal of the inverted image, for example, when the image signal level of the secret image is set to the positive direction, an image signal having the same absolute value as that of the secret image and the image signal level of the negative direction is generated. do it.
　セレクタ１５は、第１の輝度変調部１２から出力された公衆画像の画像信号、第２の輝度変調部１３から出力された秘密画像の画像信号または反転画像生成部１４で生成された反転画像の画像信号を、制御部１８からの指示にしたがって切り替え、ビデオメモリ１７に順次出力する。 The selector 15 selects the image signal of the public image output from the first luminance modulation unit 12, the image signal of the secret image output from the second luminance modulation unit 13, or the reverse image generated by the reverse image generation unit 14. The image signals are switched in accordance with instructions from the control unit 18 and are sequentially output to the video memory 17.
　同期信号発生部１６は、公衆画像の表示開始、表示終了に同期する公衆画像用同期信号と、秘密画像の表示開始、表示終了に同期する秘密画像用同期信号とを生成して送信する。 The synchronization signal generator 16 generates and transmits a public image synchronization signal synchronized with the display start and display end of the public image and a secret image synchronization signal synchronized with the display start and display end of the secret image.
　制御部１８は、表示部１９で表示する画像のフレーム構成に対応してセレクタ１５及び同期信号発生部１６の動作を制御する。 The control unit 18 controls the operations of the selector 15 and the synchronization signal generating unit 16 in accordance with the frame configuration of the image displayed on the display unit 19.
　ビデオメモリ１７は、セレクタ１５で選択された公衆画像、秘密画像または反転画像の画像信号を画像データとして順次保持する。なお、ビデオメモリ１７は、表示装置１ではなく、送信装置３に備えていてもよい。 The video memory 17 sequentially holds the image signal of the public image, the secret image or the reverse image selected by the selector 15 as image data. Note that the video memory 17 may be provided not in the display device 1 but in the transmission device 3.
　表示部１９は、ビデオメモリ１７に格納された画像データにしたがって公衆画像、秘密画像または反転画像を順次表示する。 The display unit 19 sequentially displays a public image, a secret image, or a reverse image according to the image data stored in the video memory 17.
　図２に示す送信装置３は、画像信号を処理するためのＡ／Ｄ変換器、プログラムにしたがって処理を実行するＣＰＵ、ＤＳＰあるいは論理演算回路等によって実現できる。また、表示装置１には、液晶ディスプレイ、ＬＥＤディスプレイ、ＤＬＰ型のプロジェクター装置、有機ＥＬディスプレイ、ＰＤＰ等を用いることができる。 The transmission device 3 shown in FIG. 2 can be realized by an A / D converter for processing an image signal, a CPU, a DSP, a logical operation circuit, or the like that executes processing according to a program. The display device 1 may be a liquid crystal display, an LED display, a DLP type projector device, an organic EL display, a PDP, or the like.
　図３に示すように、受信装置２は、撮影部２１、同期信号処理部２２、掛算器分配器２３、埋込信号処理部２４、ビデオメモリ２５、表示部２６、送受信部２７、制御部２８、音信号処理部２９及び通信部３０を備えた構成である。 As illustrated in FIG. 3, the reception device 2 includes an imaging unit 21, a synchronization signal processing unit 22, a multiplier distributor 23, an embedded signal processing unit 24, a video memory 25, a display unit 26, a transmission / reception unit 27, and a control unit 28. The sound signal processing unit 29 and the communication unit 30 are provided.
　撮影部２１は、カメラを備え、表示装置１の表示部１９に表示された画像を同期信号処理部２２からの指示にしたがって撮影し、掛算器分配器２３に出力する。 The photographing unit 21 includes a camera, photographs an image displayed on the display unit 19 of the display device 1 in accordance with an instruction from the synchronization signal processing unit 22, and outputs the image to the multiplier / distributor 23.
　同期信号処理部２２は、送信装置３から送信された公衆画像用同期信号及び秘密画像用同期信号を受信する受信手段を備え、受信した公衆画像用同期信号及び秘密画像用同期信号に基づいて撮影部２１に公衆画像または秘密画像の撮影タイミングを指示すると共に公衆画像用同期信号または秘密画像用同期信号を掛算器分配器２３に出力する。 The synchronization signal processing unit 22 includes a receiving unit that receives the public image synchronization signal and the secret image synchronization signal transmitted from the transmission device 3, and captures images based on the received public image synchronization signal and secret image synchronization signal. The unit 21 is instructed to shoot the public image or the secret image, and outputs the public image synchronization signal or the secret image synchronization signal to the multiplier distributor 23.
　公衆画像用同期信号及び秘密画像用同期信号は、赤外線等を利用した光通信手段、あるいはＢｌｕｅｔｏｏｔｈ、ＵＷＢ、ＺｉｇＢｅｅ等の周知の短距離無線通信手段を用いて、送信装置３が備える同期信号発生部１６から受信装置２が備える同期信号処理部２２へ送信される。 The public image synchronization signal and the secret image synchronization signal are obtained by using an optical communication means using infrared rays or a known short-range wireless communication means such as Bluetooth, UWB, ZigBee, etc. 16 to the synchronization signal processing unit 22 included in the receiving device 2.
　掛算器分配器２３は、撮影部２１から出力された公衆画像または秘密画像の画像信号の輝度（画像信号レベル）を変更し、ビデオメモリ２５及び埋込信号処理部２４に分配する。 The multiplier distributor 23 changes the luminance (image signal level) of the image signal of the public image or secret image output from the photographing unit 21 and distributes it to the video memory 25 and the embedded signal processing unit 24.
　ビデオメモリ２５は、掛算器分配器２３または制御部２８から出力された画像信号を画像データとして格納する。 The video memory 25 stores the image signal output from the multiplier distributor 23 or the control unit 28 as image data.
　表示部２６は、ビデオメモリ２５に格納された画像データにしたがって公衆画像または秘密画像を表示する。 The display unit 26 displays a public image or a secret image according to the image data stored in the video memory 25.
　埋込信号処理部２４は、撮影部２１で取得した秘密画像の画像信号に対して所要の信号処理を実行する。例えば、撮影部２１で撮影した秘密画像が二次元コードであった場合、埋込信号処理部２４は該二次元コードをデコードする。埋込信号処理部２４の信号処理の結果は制御部２８に出力される。 The embedded signal processing unit 24 performs necessary signal processing on the image signal of the secret image acquired by the imaging unit 21. For example, when the secret image photographed by the photographing unit 21 is a two-dimensional code, the embedded signal processing unit 24 decodes the two-dimensional code. The signal processing result of the embedded signal processing unit 24 is output to the control unit 28.
　制御部２８は、埋込信号処理部２４の信号処理の結果に基づき、送受信部２７や通信部３０を用いてネットワークあるいはデータサーバ４から音声（音楽等を含む）データ、文字データ、画像データ、動画像データ等の各種のコンテンツデータを取得する。制御部２８は、例えば埋込信号処理部２４の信号処理の結果によりＵＲＬを取得した場合は、通信部３０を用いて該ＵＲＬで指定されるネットワーク内のサーバ装置等から各種のコンテンツデータを取得し、埋込信号処理部２４の信号処理の結果によりデータサーバ４へのアクセスデータを取得した場合は、送受信部２７を用いてデータサーバ４から各種のコンテンツデータを取得する。取得した音声データは音信号処理部２９へ出力され、文字データ、画像データ、動画像データ等はビデオメモリ２５に画像データとして格納される。 Based on the signal processing result of the embedded signal processing unit 24, the control unit 28 uses the transmission / reception unit 27 and the communication unit 30 to transmit voice (including music) data, character data, image data, Various content data such as moving image data is acquired. For example, when the URL is acquired based on the signal processing result of the embedded signal processing unit 24, the control unit 28 acquires various content data from a server device or the like in the network specified by the URL using the communication unit 30. When the access data to the data server 4 is acquired as a result of the signal processing of the embedded signal processing unit 24, various content data are acquired from the data server 4 using the transmission / reception unit 27. The acquired sound data is output to the sound signal processing unit 29, and character data, image data, moving image data, and the like are stored in the video memory 25 as image data.
　音信号処理部２９は、音声信号を増幅する増幅器や音声を出力するスピーカ等を備え、制御部２８から供給された音声データを音声信号に変換し、スピーカにより音声を出力する。 The sound signal processing unit 29 includes an amplifier that amplifies an audio signal, a speaker that outputs audio, and the like, converts audio data supplied from the control unit 28 into an audio signal, and outputs audio through the speaker.
　送受信部２７は、データサーバ４と通信可能に接続され、制御部２８の指示にしたがってデータサーバ４から各種のコンテンツデータを受信する。送受信部２７とデータサーバ４とは、赤外線等を利用した光通信手段、あるいはＢｌｕｅｔｏｏｔｈ、ＵＷＢ、ＺｉｇＢｅｅ等の周知の短距離無線通信手段を用いて各種のコンテンツデータを送受信すればよい。 The transmitting / receiving unit 27 is communicably connected to the data server 4 and receives various content data from the data server 4 in accordance with instructions from the control unit 28. The transmission / reception unit 27 and the data server 4 may transmit and receive various types of content data using optical communication means using infrared rays or the like, or well-known short-range wireless communication means such as Bluetooth, UWB, ZigBee.
　通信部３０は、周知の無線通信手段によりインターネット等のネットワークと通信可能に接続され、制御部２８の指示にしたがってネットワーク内のＵＲＬで指定されるサーバ装置等から各種のコンテンツデータを受信する。 The communication unit 30 is communicably connected to a network such as the Internet by a known wireless communication unit, and receives various content data from a server device or the like specified by a URL in the network according to an instruction from the control unit 28.
　受信装置２には、画像を撮影するためのカメラ及び送信装置３から送信された公衆画像用同期信号及び秘密画像用同期信号を受信する受信装置を備えた、携帯電話機やＰＤＡ（Personal　Digital　Assistant）、あるいはノート型のパーソナルコンピュータ等の携帯端末装置が用いられる。 The receiving device 2 includes a mobile phone and a PDA (Personal Digital Assistant) equipped with a camera for taking an image and a receiving device for receiving the public image synchronization signal and the secret image synchronization signal transmitted from the transmission device 3. Alternatively, a portable terminal device such as a notebook personal computer is used.
　次に第１の実施の形態の送信装置３の動作について図面を用いて説明する。 Next, the operation of the transmission device 3 according to the first embodiment will be described with reference to the drawings.
　図４は第１の実施の形態の送信装置の動作例を示す模式図である。 FIG. 4 is a schematic diagram illustrating an operation example of the transmission apparatus according to the first embodiment.
　図４に示すように、第１の実施の形態の送信装置３は、上述したセキュアディスプレイ技術と同様に、１フレーム内で、公衆画像、秘密画像、反転画像を時分割で表示する。１フレーム内における、公衆画像、秘密画像、反転画像の表示順は任意とする。同期信号発生部１６は、公衆画像の表示開始、表示終了に同期する公衆画像用同期信号と、秘密画像の表示開始、表示終了に同期する秘密画像用同期信号とを送信する。 As shown in FIG. 4, the transmission apparatus 3 according to the first embodiment displays a public image, a secret image, and an inverted image in a time-division manner within one frame, as in the above-described secure display technology. The display order of public images, secret images, and reverse images within one frame is arbitrary. The synchronization signal generator 16 transmits a public image synchronization signal synchronized with the display start and display end of the public image, and a secret image synchronization signal synchronized with the display start and display end of the secret image.
　受信装置２は、公衆画像用同期信号及び秘密画像用同期信号を同期信号処理部２２でそれぞれ受信し、ユーザの操作で指定された位置の公衆画像または秘密画像を撮影部２１で撮影して表示部２６に表示する。なお、秘密画像は、必ずしも表示部２６に表示する必要はなく、秘密画像の代わりに埋込信号処理部２４の信号処理の結果や、該信号処理の結果に基づいてネットワークあるいはデータサーバ４から取得した各種のコンテンツデータを表示してもよい。その場合、受信装置２は、ユーザが秘密画像を確認できる程度の時間だけ秘密画像を表示部２６に表示した後、埋込信号処理部２４の信号処理の結果やネットワークあるいはデータサーバ４から取得した各種のコンテンツデータを表示してもよい。 The receiving device 2 receives the public image synchronization signal and the secret image synchronization signal by the synchronization signal processing unit 22, respectively, and captures and displays the public image or the secret image at the position specified by the user's operation by the imaging unit 21. Displayed on the unit 26. The secret image does not necessarily have to be displayed on the display unit 26. Instead of the secret image, the secret image is acquired from the network or the data server 4 based on the signal processing result of the embedded signal processing unit 24 or the signal processing result. Various kinds of content data may be displayed. In this case, the receiving device 2 displays the secret image on the display unit 26 for a time that allows the user to confirm the secret image, and then obtains the result of signal processing of the embedded signal processing unit 24 or the network or the data server 4. Various content data may be displayed.
　一般に、受信装置２として用いる携帯端末装置が備えるカメラにはＣＣＤ（Charge　Coupled　Devices）やＣＭＯＳ等の撮像素子が用いられる。これらの撮像素子を用いる撮影部２１では、通常、ノイズの低減や受光感度を向上させるために、受光量に応じてＣＣＤやＣＭＯＳで発生する電荷を一定期間（例えば、１フレームの期間）だけ積分する蓄積モードで動作する。そのため、公衆画像あるいは秘密画像の表示期間を何らかの手段で検出しないと、撮影部２１は公衆画像と秘密画像の合成画像を出力してしまう。 Generally, an image sensor such as a CCD (Charge Coupled Devices) or a CMOS is used for a camera included in a mobile terminal device used as the receiving device 2. In the photographing unit 21 using these image pickup elements, in general, in order to reduce noise and improve light reception sensitivity, charges generated in the CCD and CMOS according to the amount of received light are integrated for a certain period (for example, one frame period). Operate in accumulation mode. Therefore, if the display period of the public image or the secret image is not detected by any means, the photographing unit 21 outputs a composite image of the public image and the secret image.
　本実施形態の受信装置２は、送信装置３から送信される公衆画像用同期信号及び秘密画像用同期信号を用いて、所要の公衆画像または秘密画像の撮影時における積分期間の開始、終了を検出する。そのため、受信装置２は、ユーザの操作で指定された位置で公衆画像と秘密画像とを撮影部２１によって合成することなく撮影できる。また、本実施形態の受信装置２では、秘密画像用同期信号を用いて秘密画像を撮影するため、秘密画像と反転画像とが合成されることによる秘密画像の画質の劣化、すなわち可視光通信に用いる信号レベルの劣化が防止される。 The receiving device 2 of the present embodiment uses the public image synchronization signal and the secret image synchronization signal transmitted from the transmission device 3 to detect the start and end of the integration period when the required public image or secret image is captured. To do. Therefore, the receiving device 2 can shoot the public image and the secret image at the position designated by the user operation without being combined by the shooting unit 21. Further, in the receiving apparatus 2 of the present embodiment, since the secret image is captured using the secret image synchronization signal, the image quality of the secret image is deteriorated by combining the secret image and the inverted image, that is, for visible light communication. Deterioration of the signal level used is prevented.
　第１の実施の形態の通信システムによれば、公衆画像の美観を損なうことなく、簡易な手段によって可視光通信が可能になる。 According to the communication system of the first embodiment, visible light communication can be performed by simple means without impairing the beauty of public images.
　なお、上述したセキュアディスプレイ技術では、光シャッターとして液晶を用いているため、図５に示すように公衆画像と秘密画像間ならびに秘密画像と反転画像間にそれぞれ何も表示しない期間（ブランク）を設ける必要がある。このブランクは、液晶が非透過状態から透過状態あるいは透過状態から非透過状態に切り替わる際に一定の時間を必要とするため、秘密画像の前後で表示される公衆画像あるいは反転画像を排除して秘密画像のみを確実に透過させるために設けられている。そのため、上述したセキュアディスプレイ技術では秘密画像の輝度が低下してしまう課題がある。 In the secure display technology described above, since a liquid crystal is used as an optical shutter, a period (blank) in which nothing is displayed is provided between the public image and the secret image and between the secret image and the reverse image as shown in FIG. There is a need. This blank requires a certain amount of time when the liquid crystal is switched from the non-transmissive state to the transmissive state or from the transmissive state to the non-transmissive state. It is provided to ensure that only the image is transmitted. Therefore, the secure display technology described above has a problem that the brightness of the secret image decreases.
　一方、本実施形態の通信システムでは、受信装置２が備える撮影部２１により公衆画像あるいは秘密画像を撮影して表示するため、図４に示したように公衆画像と秘密画像間ならびに秘密画像と反転画像間にブランク期間を設ける必要がない。そのため、上述したセキュアディスプレイ技術と比べて秘密画像の輝度の低下が抑制される。
（第２の実施の形態）
　図６は第２の実施の形態の送信装置の動作例を示す模式図である。 On the other hand, in the communication system according to the present embodiment, since the public image or the secret image is captured and displayed by the imaging unit 21 provided in the receiving device 2, as shown in FIG. There is no need to provide a blank period between images. Therefore, a decrease in the brightness of the secret image is suppressed as compared with the above-described secure display technology.
(Second Embodiment)
FIG. 6 is a schematic diagram illustrating an operation example of the transmission apparatus according to the second embodiment.
　第２の実施の形態の送信装置３は、公衆画像の表示期間を秘密画像及び反転画像の表示期間よりも長く設定する。具体的には、図６に示すように公衆画像のみ表示するフレーム（以下、公衆画像フレームと称す）を設け、第１の実施の形態で示した公衆画像、秘密画像及び反転画像を時分割で表示するフレーム（以下、セキュアフレームと称す）を連続する複数の公衆画像フレーム間に周期的に挿入する。このように公衆画像の表示期間を秘密画像や反転画像の表示期間よりも長く設定すると、表示装置１で表示する公衆画像の輝度が向上してコントラストが上がるため、表示している公衆画像の画質が向上する。 The transmission device 3 according to the second embodiment sets the display period of the public image longer than the display period of the secret image and the reverse image. Specifically, as shown in FIG. 6, a frame for displaying only a public image (hereinafter referred to as a public image frame) is provided, and the public image, the secret image, and the reverse image shown in the first embodiment are time-divisionally divided. A frame to be displayed (hereinafter referred to as a secure frame) is periodically inserted between a plurality of consecutive public image frames. If the display period of the public image is set longer than the display period of the secret image or the reverse image in this way, the brightness of the public image displayed on the display device 1 is improved and the contrast is increased. Therefore, the image quality of the displayed public image is increased. Will improve.
　公衆画像フレーム及びセキュアフレームの切り替えは、送信装置３の制御部１８によりフレーム構成に合わせてセレクタ１５に最適な画像信号を選択させればよい。また、送信装置３の同期信号発生部１６は、表示装置１で表示する画像のフレーム構成に応じて公衆画像の表示開始、表示終了に同期する公衆画像用同期信号及び秘密画像の表示開始、表示終了に同期する秘密画像用同期信号を送信すればよい。表示装置１、送信装置３及び受信装置２の構成、並びにその他の動作については第１の実施の形態と同様であるため、その説明は省略する。 For switching between public image frames and secure frames, the control unit 18 of the transmission device 3 may cause the selector 15 to select an optimal image signal in accordance with the frame configuration. In addition, the synchronization signal generator 16 of the transmission device 3 starts the display of the public image according to the frame configuration of the image displayed on the display device 1, and starts the display and display of the public image synchronization signal and the secret image synchronized with the display end. A secret image synchronization signal synchronized with the end may be transmitted. Since the configurations of the display device 1, the transmission device 3, and the reception device 2 and other operations are the same as those in the first embodiment, description thereof is omitted.
　上述したセキュアディスプレイ技術では、ユーザが光シャッターを通して秘密画像を直接視認することを想定しているため、可視光通信を行う際に単に公衆画像フレームを設けると秘密画像の輝度が低下して可視光通信として実用的な輝度が得られない可能性がある。しかしながら本発明では秘密画像が受信装置２の撮影部２１によって光シャッターを通さずに直接撮影され、ビデオメモリ２５に保存されて表示される。そのため、セキュアディスプレイ技術のように秘密画像の輝度の低下を考慮する必要がない。 In the secure display technology described above, it is assumed that the user directly views the secret image through the optical shutter. Therefore, if a public image frame is simply provided when performing visible light communication, the brightness of the secret image decreases and visible light is displayed. There is a possibility that practical luminance cannot be obtained for communication. However, in the present invention, the secret image is directly photographed by the photographing unit 21 of the receiving device 2 without passing through the optical shutter, stored in the video memory 25 and displayed. Therefore, it is not necessary to consider a decrease in the brightness of the secret image unlike the secure display technology.
　なお、セキュアフレームは、図７（ａ）に示すように３つのフレーム毎に設ける構成や図７（ｂ）に示すように４つのフレーム毎に設ける構成であってもよく、５フレームあるいは６フレーム毎にセキュアフレームを設ける構成であってもよい。公衆画像フレームの数を増やすほど公衆画像の輝度が向上して公衆画像のコントラストが上がるが、公衆画像フレーム数が増えると秘密画像の取得機会が低減する。したがって、秘密画像の更新頻度が高い場合（動画表示等）や受信装置２で秘密画像を表示するまでに要する時間を短縮したい場合は、必要に応じて公衆画像フレームの増加数に上限値を設定することが好ましい。 The secure frame may be provided every three frames as shown in FIG. 7 (a), or may be provided every four frames as shown in FIG. 7 (b). The configuration may be such that a secure frame is provided for each. As the number of public image frames is increased, the brightness of the public image is improved and the contrast of the public image is increased. However, when the number of public image frames is increased, the chance of acquiring the secret image is reduced. Therefore, if the update frequency of secret images is high (video display etc.) or if it is desired to reduce the time required to display the secret image on the receiving device 2, an upper limit is set for the number of increase of public image frames as necessary. It is preferable to do.
　本実施形態によれば、第１の実施の形態と同様の効果に加えて、表示装置１で表示する公衆画像の輝度が向上してコントラストが上がるため、表示している公衆画像の画質を向上させることができる。
（第３の実施の形態）
　図８は第３の実施の形態の送信装置の動作例を示す模式図である。また、図９は第３の実施の形態の送信装置の他の動作例を示す図であり、同図（ａ）はフリッカを知覚し易い動作例、同図（ｂ）はフリッカを知覚し難い動作例を示す模式図である。表示装置１、送信装置３及び受信装置２の構成、並びにその他の動作については第１の実施の形態及び第２の実施の形態と同様であるため、その説明は省略する。 According to the present embodiment, in addition to the same effects as those of the first embodiment, the brightness of the public image displayed on the display device 1 is improved and the contrast is increased, so that the image quality of the displayed public image is improved. Can be made.
(Third embodiment)
FIG. 8 is a schematic diagram illustrating an operation example of the transmission apparatus according to the third embodiment. FIG. 9 is a diagram showing another operation example of the transmission apparatus according to the third embodiment. FIG. 9A shows an operation example in which flicker is easily perceived, and FIG. 9B shows that it is difficult to perceive flicker. It is a schematic diagram which shows an operation example. Since the configurations of the display device 1, the transmission device 3, and the reception device 2 and other operations are the same as those in the first embodiment and the second embodiment, description thereof is omitted.
　上述した第２の実施の形態では、連続する複数のフレーム毎にセキュアフレームを周期的に挿入する例を示した。しかしながら公衆画像フレームとセキュアフレームとでは表示期間の差違に起因して公衆画像の輝度が異なるため、表示装置１で表示する画像に周期的にセキュアフレームを挿入すると、公衆画像がちらつくフリッカが発生する要因となる。 In the above-described second embodiment, an example in which a secure frame is periodically inserted for each of a plurality of consecutive frames has been described. However, since the brightness of the public image differs between the public image frame and the secure frame due to the difference in display period, flickering of the public image occurs when the secure frame is periodically inserted into the image displayed on the display device 1. It becomes a factor.
　第３の実施の形態では、連続する複数の公衆画像フレームに対してセキュアフレームをランダムに挿入する（図８参照）。このようにすることで、表示装置１で表示する公衆画像のフリッカが抑制される。 In the third embodiment, secure frames are randomly inserted into a plurality of consecutive public image frames (see FIG. 8). By doing in this way, the flicker of the public image displayed on the display apparatus 1 is suppressed.
　公衆画像フレーム及びセキュアフレームの切り替えは、第２の実施の形態と同様に、送信装置３の制御部１８によりフレーム構成に合わせてセレクタ１５に最適な画像信号を選択させればよい。また、送信装置３の同期信号発生部１６は、表示するフレーム構成に応じて公衆画像の表示開始、表示終了に同期する公衆画像用同期信号及び秘密画像の表示開始、表示終了に同期する秘密画像用同期信号を送信すればよい。表示装置１、送信装置３及び受信装置２の構成、並びにその他の動作については第１の実施の形態と同様であるため、その説明は省略する。 As in the second embodiment, the public image frame and the secure frame may be switched by causing the control unit 18 of the transmission device 3 to select the optimum image signal in accordance with the frame configuration. Further, the synchronization signal generation unit 16 of the transmission device 3 includes a public image synchronization signal synchronized with the display start and display end of the public image and a secret image synchronized with the display start and display end according to the frame configuration to be displayed. A synchronization signal may be transmitted. Since the configurations of the display device 1, the transmission device 3, and the reception device 2 and other operations are the same as those in the first embodiment, description thereof is omitted.
　なお、表示装置１で表示する公衆画像のフリッカを抑制する方法としては、以下に記載する方法も有効である。 It should be noted that the following method is also effective as a method of suppressing the flicker of public images displayed on the display device 1.
　図９（ａ）に示すように、公衆画像フレーム（フレーム１）とセキュアフレーム（フレーム２）とが混在する場合、公衆画像フレームとセキュアフレームの公衆画像の画像信号レベルを等しくすると、これらのフレームにおける公衆画像の輝度の差が大きくなるため、フリッカが知覚されやすくなる。 As shown in FIG. 9A, when the public image frame (frame 1) and the secure frame (frame 2) are mixed, the image signal levels of the public image frame and the public image of the secure frame are equalized. Since the difference in luminance of public images in the image becomes large, flicker is easily perceived.
　そこで、図９（ｂ）に示すように、公衆画像フレームとセキュアフレームの公衆画像の画像信号レベルを変えてフレーム毎の公衆画像の輝度を同一にする。具体的には、第１の輝度変調部１２により、公衆画像フレームとセキュアフレームの公衆画像の表示期間の比率に応じて、公衆画像フレーム内の公衆画像の画像信号レベルを低下させる。あるいは第２の輝度変調部１３により、公衆画像フレームとセキュアフレームの公衆画像の表示期間の比率に応じて、セキュアフレーム内の公衆画像の画像信号レベルを増大させる。例えば、公衆画像フレームの表示期間がセキュアフレームの公衆画像の表示期間の３倍である場合、第１の輝度変調部１２は公衆画像フレームの画像信号レベルを１／３にする。あるいは第２の輝度変調部１３は秘密画像フレームの画像信号レベルを３倍にする。これらの方法でも表示装置１で表示する公衆画像のフリッカが抑制される。 Therefore, as shown in FIG. 9B, the luminance of the public image for each frame is made the same by changing the image signal level of the public image of the public image frame and that of the secure frame. Specifically, the first luminance modulation unit 12 reduces the image signal level of the public image in the public image frame according to the ratio of the public image display period of the public image frame and the secure frame. Alternatively, the second luminance modulation unit 13 increases the image signal level of the public image in the secure frame according to the ratio of the display period of the public image frame and the public image of the secure frame. For example, when the display period of the public image frame is three times the display period of the public image of the secure frame, the first luminance modulation unit 12 sets the image signal level of the public image frame to 1/3. Alternatively, the second luminance modulation unit 13 triples the image signal level of the secret image frame. Also in these methods, flickering of public images displayed on the display device 1 is suppressed.
　なお、上記公衆画像フレームとセキュアフレームの公衆画像の輝度を同一にするとは、フレーム毎の公衆画像の画像信号レベルのピーク値を同一にすること、フレーム毎の公衆画像の画像信号レベルの平均値を同一にすること、あるいはこれらの処理を組み合わせた処理を指す。 Note that making the brightness of the public image of the public image frame and the secure frame the same means that the peak value of the image signal level of the public image for each frame is the same, and the average value of the image signal level of the public image for each frame Are the same or a combination of these processes.
　本実施形態によれば、第１の実施の形態及び第２の実施の形態と同様の効果に加えて、表示装置１で表示する公衆画像のフリッカが抑制される。
（第４の実施の形態）
　第４の実施の形態では、受信装置２の表示部２６で表示している公衆画像と秘密画像の輝度を同一にするための方法を提案する。表示装置１、送信装置３及び受信装置２の構成は第１の実施の形態と同様であるため、その説明は省略する。 According to this embodiment, in addition to the same effects as those of the first embodiment and the second embodiment, flickering of public images displayed on the display device 1 is suppressed.
(Fourth embodiment)
In the fourth embodiment, a method for making the brightness of the public image and the secret image displayed on the display unit 26 of the receiving device 2 the same is proposed. Since the configurations of the display device 1, the transmission device 3, and the reception device 2 are the same as those in the first embodiment, description thereof is omitted.
　図１０は第４の実施の形態の受信装置の動作例を示す模式図である。 FIG. 10 is a schematic diagram illustrating an operation example of the receiving apparatus according to the fourth embodiment.
　図１０（ａ）に示すように、表示装置１で公衆画像フレームとセキュアフレームとを混在して表示している場合、送信装置３の同期信号発生部１６から公衆画像の表示開始、表示終了のタイミングに一致する公衆画像用同期信号が送信されると、受信装置２では積分期間が異なるために明るさ（輝度）が異なる公衆画像と秘密画像が得られる。そのため、受信装置２の表示部２６で表示している公衆画像を秘密画像に切り替えると、秘密画像の画面が暗くコントラストが低い画像として知覚されてしまう。 As shown in FIG. 10A, when the display device 1 displays a mixture of public image frames and secure frames, the display of the public image is started and the display end of the public image from the synchronization signal generator 16 of the transmission device 3. When a public image synchronization signal that matches the timing is transmitted, the reception apparatus 2 obtains a public image and a secret image that have different brightness (luminance) because the integration period is different. Therefore, when the public image displayed on the display unit 26 of the receiving device 2 is switched to the secret image, the screen of the secret image is perceived as an image with a dark contrast and a low contrast.
　第４の実施の形態の受信装置２は、掛算器分配器２３により、公衆画像と秘密画像の表示期間の比率に応じて、受信装置２の表示部２６で表示する公衆画像と秘密画像の輝度が同一になるように撮影部２１で取得した秘密画像の画像信号レベルを増大させる。あるいは受信装置２の表示部２６で表示する公衆画像と秘密画像の輝度が同一になるように撮影部２１で取得した公衆画像の画像信号レベルを低下させる。例えば、公衆画像用同期信号と秘密画像用同期信号に基づき公衆画像の表示期間が秘密画像の表示期間の３倍であることを検出した場合、掛算器分配器２３は秘密画像の画像信号レベルを３倍にする。あるいは掛算器分配器２３は公衆画像の画像信号レベルを１／３にする。このようにすれば公衆画像と秘密画像の輝度が同一になるため、受信装置２の表示部２６に公衆画像及び秘密画像が等しい明るさで表示される。 In the receiving device 2 of the fourth embodiment, the multiplier / distributor 23 causes the luminance of the public image and the secret image displayed on the display unit 26 of the receiving device 2 according to the ratio of the display period of the public image and the secret image. The image signal level of the secret image acquired by the photographing unit 21 is increased so as to be the same. Alternatively, the image signal level of the public image acquired by the photographing unit 21 is lowered so that the brightness of the public image and the secret image displayed on the display unit 26 of the receiving device 2 are the same. For example, when it is detected that the display period of the public image is three times the display period of the secret image based on the public image synchronization signal and the secret image synchronization signal, the multiplier distributor 23 sets the image signal level of the secret image. Triple. Alternatively, the multiplier distributor 23 sets the image signal level of the public image to 1/3. In this way, since the brightness of the public image and the secret image becomes the same, the public image and the secret image are displayed on the display unit 26 of the receiving device 2 with the same brightness.
　なお、受信装置２の表示部２６で表示している公衆画像と秘密画像の輝度を同一にするには以下のような方法もある。 It should be noted that there are the following methods for making the brightness of the public image and the secret image displayed on the display unit 26 of the receiving device 2 the same.
　図１０（ｂ）に示すように、公衆画像と秘密画像の輝度を同一にするには送信装置３の同期信号発生部１６で生成する公衆画像用同期信号の表示開始から表示終了までの期間を秘密画像の表示期間（１０（ｃ）参照）に一致させればよい。例えば、表示装置１による公衆画像の表示期間が秘密画像の表示期間の３倍である場合、同期信号発生部１６で生成する公衆画像用同期信号の表示開始から表示終了までの期間を実際の表示期間の１／３にする。 As shown in FIG. 10B, in order to make the brightness of the public image and the secret image the same, the period from the display start of the public image synchronization signal generated by the synchronization signal generation unit 16 of the transmission device 3 to the display end is set. What is necessary is just to make it correspond to the display period (refer to 10 (c)) of a secret image. For example, when the display period of the public image by the display device 1 is three times the display period of the secret image, the period from the display start to the display end of the public image synchronization signal generated by the synchronization signal generator 16 is actually displayed. Set to 1/3 of the period.
　このようにすると、受信装置２の撮影部２１における公衆画像と秘密画像の積分期間が同一になるため、受信装置２の表示部２６に表示される公衆画像と秘密画像とが等しい明るさで表示される。 In this way, since the integration period of the public image and the secret image in the photographing unit 21 of the receiving device 2 is the same, the public image and the secret image displayed on the display unit 26 of the receiving device 2 are displayed with the same brightness. Is done.
　本実施形態によれば、第１の実施の形態と同様の効果に加えて、受信装置２の表示部２６に公衆画像及び秘密画像が等しい明るさで表示される。 According to this embodiment, in addition to the same effects as those of the first embodiment, the public image and the secret image are displayed on the display unit 26 of the receiving device 2 with the same brightness.
　なお、上記公衆画像と秘密画像の輝度を同一にするとは、公衆画像及び秘密画像の画像信号レベルのピーク値を同一にすること、公衆画像及び秘密画像の画像信号レベルの平均値を同一にすること、あるいはこれらの処理を組み合わせた処理を指す。
（第５の実施の形態）
　上述したように、本発明ではセキュアディスプレイ技術を利用しているため、表示装置１は公衆画像と共に秘密画像とその反転画像を重畳した中間調（灰色）の画像を表示する。そのため、公衆画像内に暗い（黒い）画像が含まれていると、その部位を実際よりも明るく感じる、いわゆる黒浮きが発生する。すなわち、表示装置１で表示している公衆画像のコントラストが低下する。 Note that the same brightness of the public image and the secret image means that the peak value of the image signal level of the public image and the secret image is the same, and the average value of the image signal level of the public image and the secret image is the same. Or a combination of these processes.
(Fifth embodiment)
As described above, since the secure display technology is used in the present invention, the display device 1 displays a public image and a halftone (gray) image in which the secret image and its inverted image are superimposed. For this reason, when a dark (black) image is included in the public image, a so-called black float occurs in which the part feels brighter than the actual image. That is, the contrast of the public image displayed on the display device 1 is lowered.
　第５の実施の形態では、表示装置１で表示している公衆画像内に暗い部位がある場合、送信装置３は、その主要な色を判断し、それに対応する青色または赤色の秘密画像を表示装置１にセキュアフレーム内で表示させる。例えば公衆画像内の暗い部位が青色の強い画像である場合、表示装置１にセキュアフレーム内の対応する部位で青色の秘密画像とその反転画像で表示させる。このようにすると、対応する部位における秘密画像と反転画像を重畳した中間調が青色になるため、公衆画像内の暗い部位のコントラストの低下が抑制される。 In the fifth embodiment, when there is a dark part in the public image displayed on the display device 1, the transmission device 3 determines the main color and displays the corresponding blue or red secret image. The device 1 is displayed in a secure frame. For example, when the dark part in the public image is a strong blue image, the display device 1 displays the blue secret image and its reverse image on the corresponding part in the secure frame. In this way, since the halftone in which the secret image and the inverted image are superimposed in the corresponding part is blue, a decrease in contrast of the dark part in the public image is suppressed.
　また、公衆画像内の暗い部位が赤色の強い画像である場合、表示装置１にセキュアフレーム内の対応する部位で赤色の秘密画像とその反転画像を表示させる。このようにすると、対応する部位における秘密画像と反転画像を重畳した中間調が赤色になるため、公衆画像内の暗い部位のコントラストの低下が抑制される。 Also, when the dark part in the public image is a strong red image, the display device 1 displays the red secret image and its inverted image at the corresponding part in the secure frame. In this way, since the halftone in which the secret image and the inverted image are superimposed in the corresponding part is red, the decrease in contrast of the dark part in the public image is suppressed.
　さらに、公衆画像内に暗い部位が複数あり、赤色の強い画像が表示された部位と青色の強い画像が表示された部位がある場合、表示装置１にセキュアフレーム内の対応する各部位で赤色または青色の秘密画像とその反転画像を表示させる。このようにすると、対応する部位における秘密画像と反転画像を重畳した中間調が赤色または青色になるため、公衆画像内の暗い部位のコントラストの低下が抑制される。 Furthermore, when there are a plurality of dark parts in the public image, and there are a part where a strong red image is displayed and a part where a strong blue image is displayed, the display device 1 has red or red at each corresponding part in the secure frame. A blue secret image and its reverse image are displayed. In this way, since the halftone in which the secret image and the reverse image are superimposed in the corresponding part is red or blue, a decrease in contrast of the dark part in the public image is suppressed.
　但し、本実施形態では、秘密画像として、一般的なカラー画像を表示すると、秘密画像の色が正しく表示されないことになる。したがって、本実施形態で表示する秘密画像は、二次元コードや一次元コードのようなコード化された画像であることが好ましい。但し、本実施形態で表示する秘密画像は、コード化された画像に限定されるものではなく、上記の処理によって赤色や青色の部位を含むことになっても違和感の無い画像であれば、どのような画像でもよい。 However, in this embodiment, when a general color image is displayed as a secret image, the color of the secret image is not displayed correctly. Therefore, the secret image displayed in the present embodiment is preferably a coded image such as a two-dimensional code or a one-dimensional code. However, the secret image displayed in the present embodiment is not limited to the coded image, and any image can be used as long as it does not feel strange even if it includes a red or blue portion by the above processing. Such an image may be used.
　なお、公衆画像内の明るい部位では、第１の実施の形態～第３の実施の形態で示したように、通常のカラー画像からなる秘密画像とその反転画像をセキュアフレーム内で表示すればよい。 Note that, as shown in the first to third embodiments, a secret image made up of a normal color image and its inverted image may be displayed in a secure frame at a bright part in a public image. .
　また、秘密画像と反転画像を青または赤で表示する場合、公衆画像では青または赤がより強く表示される。したがって、公衆画像の青または赤の画像信号レベルを、秘密画像と反転画像を重畳した中間調の画像信号レベルに合わせて低下させれば、秘密画像と反転画像全体を青または赤の画像で表示することも可能である。 Also, when the secret image and the reverse image are displayed in blue or red, blue or red is displayed stronger in the public image. Therefore, if the blue or red image signal level of the public image is lowered according to the halftone image signal level in which the secret image and the inverted image are superimposed, the secret image and the entire inverted image are displayed as a blue or red image. It is also possible to do.
　第５の実施の形態の送信装置３は、図２に示したレベル検出部１１によって公衆画像の画像信号レベル及び色を予め設定された所定の大きさの領域毎に検出し、その検出結果を第１の輝度変調部１２及び第２の輝度変調部１３に通知する。第１の輝度変調部１２は、レベル検出部１１の検出結果に基づき、必要に応じて公衆画像の青または赤の画像信号レベルを低下させて出力する。 In the transmission device 3 of the fifth embodiment, the level detection unit 11 shown in FIG. 2 detects the image signal level and color of a public image for each area of a predetermined size, and the detection result is obtained. The first luminance modulation unit 12 and the second luminance modulation unit 13 are notified. Based on the detection result of the level detection unit 11, the first luminance modulation unit 12 reduces and outputs the blue or red image signal level of the public image as necessary.
　第２の輝度変調部１３は、レベル検出部１１の検出結果に基づいて、予め設定された所定の大きさの領域毎に、あるいは秘密画像全体を青または赤の画像に変換して出力する。送信装置３のその他の構成、並びに表示装置１及び受信装置２の構成は第１の実施の形態と同様であるため、その説明は省略する。 Based on the detection result of the level detection unit 11, the second luminance modulation unit 13 outputs an area of a predetermined size set in advance or converts the entire secret image into a blue or red image. Since the other configurations of the transmission device 3 and the configurations of the display device 1 and the reception device 2 are the same as those in the first embodiment, description thereof is omitted.
　本実施形態によれば、第１の実施の形態と同様の効果に加えて、表示装置１で表示している公衆画像に暗い部位が含まれていても、コントラストの低下が抑制されて画質を向上させることができる。 According to the present embodiment, in addition to the same effects as those of the first embodiment, even when a dark part is included in the public image displayed on the display device 1, a decrease in contrast is suppressed and the image quality is improved. Can be improved.
　以上、実施形態を参照して本願発明を説明したが、本願発明は上記実施形態に限定されものではない。本願発明の構成や詳細は本願発明のスコープ内で当業者が理解し得る様々な変更が可能である。 As mentioned above, although this invention was demonstrated with reference to embodiment, this invention is not limited to the said embodiment. Various modifications that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention.
　この出願は、２００８年３月１０日に出願された特願２００８－０５９９６９号を基礎とする優先権を主張し、その開示の全てをここに取り込む。 This application claims priority based on Japanese Patent Application No. 2008-059969 filed on Mar. 10, 2008, the entire disclosure of which is incorporated herein.

Claims (17)

  1. 　第１の画像と第２の画像と該第２の画像の反転画像とを時分割で表示するための画像信号を出力すると共に、前記第２の画像の表示と同期する第２の画像用同期信号を送信する送信装置と、
    　前記送信装置より出力された画像信号に基づく画像を表示する表示装置と、
    　前記第２の画像用同期信号を受信し、前記第２の画像用同期信号を用いて前記送信装置に表示された前記第２の画像を前記撮影部により撮影する受信装置と、
    を有する通信システム。     Second image synchronization that outputs an image signal for displaying the first image, the second image, and an inverted image of the second image in a time-division manner, and is synchronized with the display of the second image A transmission device for transmitting a signal;
    A display device for displaying an image based on the image signal output from the transmission device;
    A receiver that receives the second image synchronization signal, and that captures the second image displayed on the transmitter using the second image synchronization signal, by the imaging unit;
    A communication system.
  2. 　前記送信装置は、
    　前記第１の画像の表示と同期する第１の画像用同期信号を送信し、
    　前記受信装置は、
    　前記第１の画像用同期信号を受信し、前記第１の画像用同期信号を用いて前記表示装置に表示された前記第１の画像を撮影部により撮影して表示部に表示する請求項１記載の通信システム。     The transmitter is
    Transmitting a first image synchronization signal synchronized with the display of the first image;
    The receiving device is:
    The first image synchronization signal is received, and the first image displayed on the display device is photographed by the photographing unit using the first image synchronization signal, and displayed on the display unit. The communication system described.
  3. 　前記送信装置は、
    　前記第１の画像の表示期間を前記第２の画像及び前記反転画像の表示期間よりも長く設定する請求項１または２記載の通信システム。     The transmitter is
    The communication system according to claim 1 or 2, wherein a display period of the first image is set longer than a display period of the second image and the reverse image.
  4. 　前記送信装置は、
    　前記第１の画像のみ表示する第１の画像フレームと、前記第１の画像、前記第２の画像及び前記反転画像を時分割で表示する第２の画像フレームとを用いて、前記第１の画像、前記第２の画像及び前記反転画像を表示する請求項３記載の通信システム。     The transmitter is
    Using the first image frame that displays only the first image and the second image frame that displays the first image, the second image, and the inverted image in a time-sharing manner, the first image frame is displayed. The communication system according to claim 3, wherein an image, the second image, and the inverted image are displayed.
  5. 　前記送信装置は、
    　連続する複数の前記第１の画像フレームに対して前記第２の画像フレームをランダムに挿入する請求項４記載の通信システム。     The transmitter is
    The communication system according to claim 4, wherein the second image frame is randomly inserted into the plurality of continuous first image frames.
  6. 　前記送信装置は、
    　前記第１の画像フレームの第１の画像の輝度と前記第２の画像フレームに含まれる第１の画像の輝度とが同一になるように、前記第１の画像フレームと前記第２の画像フレームに含まれる第１の画像の表示期間の比率に応じて、前記第１の画像フレームの第１の画像の画像信号レベルまたは前記第２の画像フレームに含まれる第１の画像の画像信号レベルを変更する請求項４記載の通信システム。     The transmitter is
    The first image frame and the second image frame so that the luminance of the first image of the first image frame and the luminance of the first image included in the second image frame are the same. The image signal level of the first image included in the first image frame or the image signal level of the first image included in the second image frame according to the ratio of the display period of the first image included in The communication system according to claim 4 to be changed.
  7. 　前記送信装置は、
    　前記第２の画像がコード化された画像である場合、前記第２の画像及び前記反転画像に、青または赤の画像を含めて表示する請求項１記載の通信システム。     The transmitter is
    The communication system according to claim 1, wherein when the second image is an encoded image, the second image and the reverse image are displayed including a blue or red image.
  8. 　第１の画像、第２の画像及び該第２の画像の反転画像を表示する表示部と、
    　前記第１の画像、前記第２の画像及び前記反転画像を前記表示部に時分割で表示させるための制御部と、
    　前記第２の画像の表示と同期する第２の画像用同期信号を送信する同期信号発生部と、
    を有する送信装置。     A display unit for displaying the first image, the second image, and a reverse image of the second image;
    A control unit for displaying the first image, the second image, and the inverted image on the display unit in a time-sharing manner;
    A synchronization signal generator for transmitting a second image synchronization signal synchronized with the display of the second image;
    A transmission device.
  9. 　前記同期信号発生部は、
    　前記第１の画像の表示と同期する第１の画像用同期信号を送信する送信装置。     The synchronization signal generator is
    A transmission device that transmits a first image synchronization signal synchronized with the display of the first image.
  10. 　前記制御部は、
    　前記第１の画像の表示期間を前記第２の画像及び前記反転画像の表示期間よりも長く設定する請求項８または９記載の送信装置。     The controller is
    The transmission device according to claim 8 or 9, wherein a display period of the first image is set longer than a display period of the second image and the reverse image.
  11. 　前記制御部は、
    　前記第１の画像のみ表示する第１の画像フレームと、前記第１の画像、前記第２の画像及び前記反転画像を時分割で表示する第２の画像フレームとを用いて、前記第１の画像、前記第２の画像及び前記反転画像を前記表示部に表示させる請求項１０記載の送信装置。     The controller is
    Using the first image frame that displays only the first image and the second image frame that displays the first image, the second image, and the inverted image in a time-sharing manner, The transmission device according to claim 10, wherein an image, the second image, and the inverted image are displayed on the display unit.
  12. 　前記制御部は、
    　連続する複数の前記第１の画像フレームに対して前記第２の画像フレームをランダムに挿入する請求項１１記載の送信装置。     The controller is
    The transmission device according to claim 11, wherein the second image frame is randomly inserted into the plurality of continuous first image frames.
  13. 　前記第１の画像フレームの第１の画像の輝度と前記第２の画像フレームに含まれる第１の画像の輝度を検出するレベル検出部と、
    　前記第１の画像フレームの第１の画像の輝度と前記第２の画像フレームに含まれる第１の画像の輝度とが同一になるように、前記第１の画像フレームと前記第２の画像フレームに含まれる第１の画像の表示期間の比率に応じて、前記第１の画像フレームの第１の画像の画像信号レベルまたは前記第２の画像フレームに含まれる第１の画像の画像信号レベルを変更する第１の輝度変調部と、
    をさらに有する請求項１１記載の送信装置。     A level detection unit that detects the luminance of the first image of the first image frame and the luminance of the first image included in the second image frame;
    The first image frame and the second image frame so that the luminance of the first image of the first image frame and the luminance of the first image included in the second image frame are the same. The image signal level of the first image included in the first image frame or the image signal level of the first image included in the second image frame according to the ratio of the display period of the first image included in A first luminance modulation section to be changed;
    The transmission device according to claim 11, further comprising:
  14. 　前記第２の画像がコード化された画像である場合、前記第２の画像及び前記反転画像に、青または赤の画像を含めるための第２の輝度変調部をさらに有する請求項１３記載の送信装置。 14. The transmission according to claim 13, further comprising a second luminance modulation unit for including a blue or red image in the second image and the inverted image when the second image is a coded image. apparatus.
  15. 　送信装置から送信される、第２の画像の表示と同期する第２の画像用同期信号を受信し、受信した前記第２の画像用同期信号に基づいて、前記第２の画像の撮影タイミングを指示する同期信号処理部と、
    　前記同期信号処理部からの指示にしたがって前記第２の画像を撮影する撮影部と、
    　前記撮影部で撮影された前記第２の画像を表示する表示部と、
    を有する受信装置。     A second image synchronization signal synchronized with the display of the second image transmitted from the transmission device is received, and the shooting timing of the second image is determined based on the received second image synchronization signal. A synchronization signal processing unit for instructing;
    An imaging unit that captures the second image according to an instruction from the synchronization signal processing unit;
    A display unit for displaying the second image photographed by the photographing unit;
    A receiving apparatus.
  16. 　前記同期信号処理部は、
    　送信装置から送信される、第１の画像の表示と同期する第１の画像用同期信号を受信し、受信した前記第１の画像用同期信号に基づいて、前記第１の画像の撮影タイミングを前記撮影部に指示し、
    　前記撮影部は、
    　前記同期信号処理部からの指示にしたがって前記第１の画像を撮影し、
    　前記表示部は、
    　前記撮影部で撮影された、少なくとも前記第１の画像を表示する請求項１５記載の受信装置。     The synchronization signal processing unit
    The first image synchronization signal synchronized with the display of the first image transmitted from the transmission device is received, and the photographing timing of the first image is determined based on the received first image synchronization signal. Instruct the shooting unit,
    The photographing unit
    Taking the first image according to an instruction from the synchronization signal processing unit,
    The display unit
    The receiving device according to claim 15, wherein at least the first image captured by the imaging unit is displayed.
  17. 　前記送信装置が、前記第１の画像のみ表示する第１の画像フレームと前記第１の画像、前記第２の画像及び該第２の画像の反転画像を時分割で表示する第２の画像フレームとを用いて前記第１の画像、前記第２の画像及び前記反転画像を表示しているとき、前記第１の画像と前記第２の画像の輝度が同一になるように、前記撮影部で撮影された前記第１の画像の画像信号レベルまたは前記第２の画像の画像信号レベルを変更する掛算器分配部をさらに有する請求項１５または１６記載の受信装置。 The transmission apparatus displays a first image frame that displays only the first image, a second image frame that displays the first image, the second image, and an inverted image of the second image in a time-sharing manner. When the first image, the second image, and the reverse image are displayed using the image capturing unit, the photographing unit causes the luminance of the first image and the second image to be the same. The receiving device according to claim 15 or 16, further comprising a multiplier distributor for changing an image signal level of the photographed first image or an image signal level of the second image.
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